The harvesting of fruit, such as berries, from fruit bearing bushes and vines which are planted in rows, involves a number of practical and economic considerations. First, there is a requirement that the berries be harvested as quickly as possible. A typical berry harvesting season may last four to six weeks. When the berries ripen, there is a short time span in which they must be picked or they will overripen and become unmarketable. Sometimes this requires that the berries be harvested every other day during the harvesting season so that it is not uncommon for a bush to be harvested twelve to eighteen or more times in a single season. To accomplish this within the allotted time, the harvesting operation must be expeditious.
In addition to picking speed, it is desirable that only those berries which are in fact ripe be dislodged from the bushes. However, as just mentioned, the fruit on many berry plants does not ripen at the same time. Any unripe fruit which is dislodged during a picking operation is generally not suitable for market and therefore reduces the overall yield of the bush.
With the rise in cost of manual picking, an increasingly greater share of the berry picking is being done by machinery. These machines are commonly mounted on a wheeled chassis and include an enclosure formed by two spaced apart upstanding sidewalls which extend in a parallel fore and aft direction. They also include a number of mechanically driven beater rods which strike at the bushes in order to dislodge the berries when the bushes are inside the enclosure. At the bottom of the sidewalls is a collecting floor including a collecting conveyor which collects the berries as they fall from the bushes and transports them to a collecting area.
To optimize yields, it is desirable that the berries be collected in a manner that the loosely held ripe fruit is dislodged from the bushes, while the more tightly held unripe fruit remains on the bushes to ripen. With berry bushes, however, many of the berries grow on long laterally extending fruit spurs which grow outwardly from the bush, but which constitute new growth and therefore are somewhat fragile and subject to easily breaking off. However, a dislodging force which is not sufficient to dislodge an unripe berry from the fruit spur, may be sufficient to break off the fruit spur from the bush, resulting in the loss of those unripe berries. Thus, the harvesting of berries is a tradeoff between speed of harvesting versus damage to the berry bush and resulting decreasing yield. That is, in a conventional operation, greater harvesting speed is often achieved by increasing the speed and impact force of the beater rods upon the bushes in order to increase the rate at which the berries are dislodged. The greater speed and impact of the beater rods, however, causes many of these fruit spurs to be broken off from the bushes and thereby decreases the overall fruit yield of the bush.
As indicated above, a factor instrumental in the harvesting of berries is the maximization of the collection yield of berries which have been dislodged from the bushes. Collection of these berries by the berry picking machines is typically performed by the collecting plates which are located on the floor of the machine. In conventional berry picking machines, some of the fruit is dislodged from the bushes both in front and behind the machine and therefore is not collected within the enclosure. This is a result of the bushes being closely engaged in longitudinally extending rows so that movement of the bush by the beater rods within the harvester enclosure is transmitted or "telegraphed" forwardly and rearwardly from the machine to those bushes outside the enclosure. The resulting movement of the bushes outside the harvester enclosure not only causes those unpicked ripe berries in front of the machine to be dislodged and fall to the ground where the machine is unable to collect them, but it can cause those ripe berries which are still attached to the bushes behind the machine to fall to the ground.
Other conventional apparatus and methods for harvesting fruit have been disclosed. For example, a harvester having reciprocating beater elements is disclosed in U.S. Pat. No. 3,686,842 and U.S. Pat. No. 3,685,264, both by Littau. Harvesters having (i) vibrating beater elements are shown in U.S. Pat. No. 3,485,027 by Ganger; (ii) rotating beater elements are shown in U.S. Pat. No. 3,245,211 by Weygandt et al; (iii) beater elements with different phases are shown in U.S. Pat. No. 3,939,629 by Bruel; and (iv) adjustable variable angle beater elements are shown in U.S. Pat. No. 4,435,950 by Deux et al.
In addition to the aforementioned harvesting machines, harvesters having beater elements which are mounted to movable upstanding posts have been disclosed. These include laterally and/or angularly adjustable posts as shown in U.S. Pat. No. 3,184,908 by Rust; U.S. Pat. No. 3,473,311 by Fox; U.S. Pat. No. 3,890,774 by Bruel; as well as U.S. Pat. No. 4,022,001; U.S. Pat. No. 4,292,792; and U.S. Pat. No. 4,063,406, all by Burton. Furthermore, spring biased laterally movable beater support posts are disclosed in U.S. Pat. No. 3,478,501 by Patzlaff; and U.S. Pat. No. 4,114,463 by Garden et al.
Other harvesters having laterally extending beater elements mounted to upstanding posts for horizontal and/or vertical movement are disclosed in U.S. Pat. No. 3,727,388 by Smith; and U.S. Pat. No. 4,251,983 by Burton. In U.S. Pat. No. 4,282,705 by Fontan, the beater elements are inclined from the horizontal. In Patzlaff, U.S. Pat. No. 3,611,689, two sets of beater elements are shown, one set being staggered longitudinally behind the other set of beater elements. Two pairs of longitudinally separated beater elements are also shown in U.S. Pat. No. 4,251,983 by Burton.
Additional harvesting machines are also disclosed in U.S. Pat. No. 2,671,301 by Harrison; U.S. Pat. No. 3,768,240 by Lyon; U.S. Pat. No. 2,447,122 by Horst, Jr.; and U.S. Pat. No. 4,445,316 by Browning et al.